Majin Tensei is the first game in the Majin Tensei series and was released for the Super Famicom. Majin Tensei and its successors put a turn-based strategy twist on the usual Megami Tensei gameplay formula.
The manga adaptation of Majin Tensei is known as Majin Tensei: The True Remembrance, which has a similar plot, although with a few changes. It ran from April 1994 to August 1996.
In the late 1990s, ethnic battles around the world result in a large amount of deaths and a large portion of the world being closed off. Decades later, in 202X, a boy living in Neider Tokyo in the area D-03 suddenly receives a mysterious Demon Summoning Program on his COMP from someone called TAKEUCHI, with demons appearing immediately after. After fighting his way to a mysterious building, he finds a young woman in cryogenic sleep, who decides to join him. There are 3 possible endings: a bad ending, a normal ending, and the best ending.
The bad ending is received if the player kills any demon during chapter 51. This is the only way to get that ending, and is presumably gotten due to killing non-hostile, extremely weak demons.
The normal ending is received if the player doesn't kill any demons in chapter 51, but doesn't fulfill any of the requirements for the best ending.
The best ending is received by not killing any demons in chapter 51, and then managing to fulfill the many requirements for obtaining this ending (e.g., letting the protagonist sacrifice himself to obtain the Hinokagutsuchi's power rather than the Heroine or a demon, not killing Lucifer).